The present invention relates to medical catheters, and more particularly, to exchange catheters and methods of using such catheters.
Catheters are long, tube-like devices inserted into the body for various diagnostic and therapeutic purposes. Guide wires are often used to lead or guide the catheters to the desired location in the patient's body. For example, in percutaneous transluminal coronary angioplasty (PTCA), a guidewire is first inserted into the patient's femoral artery and is advanced to the site of a stenosis or occlusion. Fluoroscopy is used to view the arterial system in order to navigate the wire through the vasculature. A guide catheter is then typically inserted along the guidewire to a point just proximal to the occlusion.
Often, it is desirable to remove the first guidewire, and insert a second guidewire. The first guidewire may be exchanged for a second guidewire that is different in size or stiffness, or of a different shape, for example. The guidewires are exchanged while the guide catheter remains in place, and the wires are withdrawn and inserted through the catheter. The guide catheter may therefore also be known as an exchange catheter, or introducer.
In PTCA, an angioplasty catheter having an inflatable balloon at its distal end is inserted through the guide catheter and over the guidewire, until the angioplasty balloon is in place at the site of the occlusion. The balloon is then inflated to reduce the size of the occlusion and restore blood flow through the vessel.
It is preferable that the guide catheter or exchange catheter has as small a profile, i.e., transverse dimension, or outer diameter, as possible, especially at its distal tip. This is to reduce the risk of hematoma at the site of insertion in the femoral artery or other vessel, and to reduce the risk of injury to the vessels during advancement and removal of the catheter.
There is therefore a need for an exchange catheter which will allow for the exchange of guidewires and facilitate the insertion of occlusive devices, while also having a low profile to prevent damage to the patient's blood vessels.